JP2020069745A - Manufacturing method of tire - Google Patents

Abstract

To provide a manufacturing method of a tire with superior uniformity.SOLUTION: The manufacturing method for the tire includes the steps of:(A) winding an inner liner member 18a around a drum 36; (B) winding a carcass ply member 28a around the wound inner liner member 18a to form a polymerization portion 54 between a circumferential tip 28f and a rear end 28f of the carcass ply member 28a; and (C) adsorbing the inner liner member 18a at an adsorption hole 54 formed on an outer periphery surface 36a of the drum 36, crimping the polymerization portion 54 with a stitcher 50, and obtaining a band base 42 including the inner liner member 18a and the carcass ply member 28a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a tire manufacturing method.

  A tire is obtained by vulcanizing a raw cover. In manufacturing the raw cover, a belt-shaped carcass ply member is wound around a drum. The circumferential end of the carcass ply member is pressure bonded by a stitcher. By this pressure bonding, the carcass ply member is formed into a cylindrical shape. A cylindrical band base including the carcass ply member is formed. The band base is further combined with another rubber member to obtain a raw cover. Japanese Unexamined Patent Application Publication No. 2012-236392 describes a raw cover thus obtained.

JP2012-236392A

  In a low cover in which the circumferential end of the carcass ply member is insufficiently pressure-bonded, the overlapping portion will be opened in a later step. The opening of the overlapping portion is called joint opening. The occurrence of this joint open can be suppressed by increasing the pressure bonding pressure. On the other hand, in the raw cover where the pressure is too strong, the band base is displaced. This misalignment reduces the molding accuracy of the raw cover. This misalignment reduces the uniformity of the tire.

  An object of the present invention is to provide a method for manufacturing a tire having excellent uniformity.

The method for manufacturing a tire according to the present invention,
(A) A step of winding the inner liner member around the drum,
(B) A step of winding a carcass ply member around the wound inner liner member to form a superposed portion of a front end portion and a rear end portion in the circumferential direction of the carcass ply member, and (C) an outer peripheral surface of the drum. The method includes the step of pressing the polymerized portion with a stitcher in a state where the inner liner member is sucked by the formed suction holes to obtain a band substrate including the inner liner member and the carcass ply member.

  Preferably, the pitch of the suction holes of the drum is 200 mm or more and 250 mm or less in the axial direction of the drum.

  Preferably, in the step (C), the pressure for pressing the stitcher is 0.25 MPa or more and 0.40 MPa or less.

This manufacturing method is
(D) The method further includes the step of holding and transporting the wound band base with a band holder.
Preferably, in the step (C), the overlapping portion is pressure-bonded by the stitcher supported by the band holder while the band holder relatively moves relative to the drum toward a position for holding the band base.

  In the tire manufacturing method according to the present invention, the polymerized portion is pressure-bonded with the stitcher while the inner liner member is suctioned by the suction holes. In this manufacturing method, the displacement of the carcass ply member is suppressed when the overlapping portion is pressure-bonded. The tire obtained by this manufacturing method is excellent in uniformity.

FIG. 1 is a sectional view of a tire obtained by the manufacturing method of the present invention. FIG. 2 is a conceptual diagram of a molding apparatus used in the manufacturing method of the present invention. 3 (a) is a front view of the drum of the molding apparatus of FIG. 2, and FIG. 3 (b) is a sectional view taken along the line segment IIIb-IIIb of FIG. 3 (a). FIG. 4 is an explanatory view showing a usage state of the molding apparatus of FIG. FIG. 5 is an explanatory diagram of the positional deviation evaluation of the band base member wound around the drum of FIG.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

  FIG. 1 illustrates a tire 2 obtained by the manufacturing method according to the present invention. The tire 2 includes a tread 4, a pair of sidewalls 6, a pair of clinches 8, a pair of beads 10, a carcass 12, a belt 14, a band 16, an inner liner 18, and a pair of chafers 20.

  The tread 4 forms a tread surface 22 that contacts the road surface. Each sidewall 6 extends substantially inward in the radial direction from the end of the tread 4. Each clinch 8 comes into contact with the flange of the rim when the tire 2 is mounted on the rim. Each bead 10 is located inside the sidewall 6 in the radial direction. The bead 10 includes a core 24 and an apex 26 extending outward from the core 24 in the radial direction.

  The carcass 12 includes a carcass ply 28. The carcass ply 28 is bridged between the beads 10 on both sides. The carcass ply 28 includes a large number of cords and a topping rubber arranged in parallel. The carcass 12 may include two or more carcass plies.

  The belt 14 is located inside the tread 4 in the radial direction. The belt 14 includes an inner layer 30 and an outer layer 32. The inner layer 30 and the outer layer 32 are composed of a large number of cords arranged in parallel and a topping rubber. The band 16 is located outside the belt 14 in the radial direction. The band 16 includes a cord and a topping rubber. The cord is spirally wound. The cord extends substantially circumferentially.

  The inner liner 18 constitutes the inner surface of the tire 2. The inner liner 18 is made of crosslinked rubber. The inner liner 18 is made of a crosslinked rubber having an excellent air shielding property. The inner liner 18 holds the internal pressure of the tire 2.

  Each chafer 20 is located near the bead 10. When the tire 2 is incorporated into the rim, the chafer 20 contacts the rim.

  The tire 2 is obtained from a raw cover (not shown). The raw cover is formed by combining members forming each part of the tire 2. Examples of members that form these parts include a tread member that forms the tread 4, a bead member that forms the beads 10, a band member that forms the band 16, and a belt member that forms the belt 14. The members forming the respective parts include an inner liner member 18a (see FIG. 4) forming the inner liner 18 and a carcass ply member 28a (see FIG. 4) forming the carcass 12.

  FIG. 2 shows a molding device 34 used for manufacturing the tire 2. The molding device 34 has a function of molding the raw cover. The molding device 34 includes a drum 36, a band transfer 38, and a shaping former 40.

  The drum 36 is used to form a cylindrical band base 42 (see FIG. 4). The band base 42 includes a cylindrical inner liner member 18a and a carcass ply member 28a. The band transfer 38 has a function of carrying the band base 42. The shaping former 40 has a function of expanding the band base 42 from a cylindrical shape to a toroidal shape.

  The band transfer 38 includes a band holder 44, a bead setter 46, a transfer device 48, and a stitcher 50. The band holder 44 has a function of holding the band base 42. The bead setter 46 has a function of holding the pair of bead members at predetermined positions.

  The transfer device 48 includes a rail 48a and a traveling platform 48b guided by the rail 48a. The band holder 44 and the bead setter 46 are attached to the traveling table 48b. A chain double-dashed line A1 in FIG. 2 represents the band holder 44, the bead setter 46, and the traveling base 48b in the first position. At the first position A1, the band holder 44 and the bead setter 46 are located outside the drum 36 in the radial direction. A chain double-dashed line A2 represents the band holder 44, the bead setter 46, and the traveling base 48b in the second position. In the second position A2, the band holder 44 and the bead setter 46 are located outside the shaping former 40 in the radial direction. The carrying device 48 has a function of moving the band holder 44 and the bead setter 46 to the first position A1 and the second position A2.

  The stitcher 50 includes a roller 50a as a pressing portion, a support portion 50b of the roller 50a, and a biasing portion 50c that biases the support portion 50b inward in the radial direction. The urging portion 50c is attached to the band holder 44. The stitcher 50 moves together with the band holder 44 when the band holder 44 moves.

  FIG. 3A shows a front view of the drum 36, and FIG. 3B shows a part of the cross section taken along the line segment IIIb-IIIb of FIG. 3A.

  The drum 36 includes a plurality of segments 52. The plurality of segments 52 are arranged in the circumferential direction to form the outer peripheral surface 36 a of the drum 36. Each segment 52 is movable in the radial direction. Thereby, the diameter of the drum 36 can be increased and decreased. The drum 36 is rotatably supported around the axis. The plurality of segments 52 includes a plurality of segments 52a and a plurality of segments 52b. A suction hole 54 is formed in each segment 52a. The suction hole 54 is connected to a vacuum device (not shown). The inside of the suction hole 54 can be depressurized by this vacuum device. No suction hole 54 is formed in each segment 52b.

  A double-headed arrow Dp in FIG. 3A represents the pitch of the suction holes 54 in the axial direction. The suction holes 54 are formed at a constant pitch Dp. A double-headed arrow θp in FIG. 3B represents a pitch angle of the suction holes 54 in the circumferential direction. The suction holes 54 are formed at equal pitch angles θp in the circumferential direction. The pitch angle θp is not particularly limited, but in the drum 36, the pitch angle θp is set to 60 °.

  FIG. 4 shows a part of the use state of the molding device 34 of FIG. In FIG. 4, the inner liner member 18a and the carcass ply member 28a are wound around the drum 36. The carcass ply member 28a is wound around the inner liner member 18a. The front end portion 28f and the rear end portion 28r of the carcass ply member 28a are overlapped with each other to form the overlapping portion 56. The stitcher 50 is pressure-bonded to the overlapping portion 56. The pressure inside the suction holes 54 is reduced, and the inner liner member 18 is suctioned to the suction holes 54.

  Here, a method for manufacturing the tire 2 of FIG. 1 will be described with reference to FIGS. 1 to 4.

  In this manufacturing method, members forming each part of the tire 2 are prepared (STEP 1). The members forming each part include a tread member, a bead member, a band member, a belt member, and the like, as well as an inner liner member 18a and a carcass ply member 28a.

  The inner liner member 18a is wound around the drum 36 of FIG. 2 (STEP 2). The tip portion of the inner liner member 18a is attached to the outer peripheral surface 36a. The inner liner member 18a is wound around the drum 36 while the drum 36 rotates.

  Further, the carcass ply member 28a is wound on the outer side of the wound inner liner member 18a (STEP 3). The tip portion 28f of the carcass ply member 28a is attached to the outer peripheral surface of the inner liner member 18. While the drum 36 rotates, the carcass ply member 28a is wound around the drum 36. In STEP 3, the front end portion 28f and the rear end portion 28r of the carcass ply member 28a are overlapped. The front end portion 28f and the rear end portion 28r form the overlapping portion 56. In the method for manufacturing the tire 2, another rubber member may be wound around the wound inner liner member 18a, and the carcass ply member 28a may be wound around the other rubber member.

  The overlapping portion 56 of the carcass ply member 28a is pressure-bonded to form the band base 42 (STE4). In STEP 4, the drum 36 is rotated in the circumferential direction so that the position of the overlapping portion 56 corresponds to the position of the stitcher 50. The band transfer 38 moves the bead setter 46 and the stitcher 50 toward the first position A1 in FIG. As shown in FIG. 4, this movement causes the stitcher 50 to crimp the overlapping portion 56 from one end in the axial direction to the other end. In this STEP 4, the inner liner member 18a is adsorbed by the adsorption holes 54. In this way, the band base 42 is formed.

  Although not shown, a bead member is pressure-bonded to the band base 42 (STEP 5). In STEP 5, the bead setter 46 holds a pair of bead members on the outer side in the radial direction of the band base 42. The drum 36 expands in diameter. As a result, the diameter of the band base 42 is expanded. The bead member is pressure-bonded to the band base body 42 whose diameter has been expanded.

  The band transfer 38 conveys the band base 42 to the second position A2 (STEP 6). In this STEP 6, the band holder 44 holds the band base 42. For example, the band holder 44 includes a plurality of suction pads arranged in the circumferential direction. The suction pad vacuum-sucks the outer peripheral surface of the band base 42. The diameter of the drum 36 is reduced, and the drum 36 is separated from the band base 42. Then, the band holder 44 moves the band base 42 to the second position A2.

  The shaping base 40 holds the band base 42 that has moved to the second position A2 (STEP 7). In STEP 7, the diameter of the shaping former 40 is expanded. The shaping former 40 holds the band base 42 at the second position A2. The band holder 44 releases the holding of the band base 42. The band holder 44 moves away from the second position A2.

  Although not shown, the tread cylinder is arranged outside the band base 42 at the second position A2 (STEP 8). This tread cylinder is formed of a tread member, a band member, a belt member, and the like. This tread cylinder has a cylindrical shape. The tread cylinder is arranged outside the band base 42 in the radial direction.

  A raw cover is formed from the band base 42 and the tread cylinder (STEP 9). In STEP 9, the shaping former 40 expands the band base 42 into a toroidal shape. The outer peripheral surface of the toroidal band base 42 is pressed against the inner peripheral surface of the tread cylinder. The band base 42 and the tread cylinder are pressure-bonded to each other to form a raw cover.

  The tire 2 is formed from this raw cover (STEP 10). In STEP 10, the raw cover is put into the mold. The raw cover is pressed and heated in the mold. The tire 2 is obtained from the raw cover.

  This manufacturing method includes STEP2 (step A), SETP3 (step B), and STEP4 (step C). In this STEP 4, the band base 42 is positioned on the drum 36 by forming the inner liner member 18 a in the suction hole 54. The stitcher 50 press-bonds the overlapping portion 56 while the inner liner member 18a is adsorbed. As a result, the band base 42 is unlikely to be displaced due to the pressure bonding of the stitcher 50. This manufacturing method can suppress a decrease in the uniformity of the tire 2.

  In this manufacturing method, the relationship between the position of the stitcher 50 and the position of the suction hole 54 in the circumferential direction is not particularly limited. However, in STEP 4, the position of the stitcher 50 and the position of the suction hole 54 are preferably aligned in the circumferential direction. Thereby, the displacement of the band base 42 due to the pressure bonding can be further suppressed.

  The drum 36 in which the pitch Dp of the suction holes 54 is small contributes to improving the uniformity of the tire 2. From this viewpoint, the pitch Dp is preferably 250 mm or less, more preferably 240 mm or less, and particularly preferably 230 mm or less. On the other hand, in the drum 36 in which the suction holes 54 have a large pitch Dp, the band base 42 is easily peeled off from the outer peripheral surface 36a. The band base 42 is easily held by the band holder 44. The drum 36 can suppress the occurrence of defective conveyance of the band base 42. The drum 36 does not hinder the productivity of the tire 2. From this viewpoint, the pitch Dp is preferably 200 mm or more, more preferably 210 mm or more.

  In this manufacturing method, since the band base 42 is less likely to be displaced, the stitcher 50 can be pressure-bonded with a larger pressure Pt than in the past. As a result, joint opening can be suppressed when the band base body 42 expands in a toroidal shape in STEP 9.

  The stitcher 50 having a large pressure Pt can suppress the joint opening. From this viewpoint, the pressure bonding pressure Pt is preferably 0.25 MPa or more, more preferably 0.26 MPa or more. On the other hand, the stitcher 50 with the pressure Pt that is too high causes the band base 42 to be displaced. This misalignment reduces the uniformity of the tire 2. From this viewpoint, the pressure bonding pressure Pt is preferably 0.40 MPa or less, more preferably 0.35 MPa or less, and particularly preferably 0.30 MPa or less.

  This crimping pressure Pt is obtained from the load pressing the stitcher 50 in the radial direction and the ground contact area of the stitcher 50. The ground contact area of the stitcher 50 is obtained as the ground contact area when the stitcher 50 is pressed against the outer peripheral surface 36a of the drum 36 with its load.

  This manufacturing method includes STEP 6 (step D). In this STEP 6, the wound band substrate 42 is held by the band holder 44 and conveyed. In STEP4 prior to STEP6, the band holder 44 moves to the first position A1 for holding the band base 42. While making this movement, the stitcher 50 press-bonds the overlapping portion 56. In this manufacturing method, the stitcher 50 presses the overlapping portion 56 while the band holder 44 moves relative to the drum 36. This manufacturing method is excellent in productivity. Here, the band holder 44 may move relative to the drum 36, the drum 36 may move, or the drum 36 and the band holder 44 may move.

  In this STEP 4, when the band transfer 38 moves to the first position A1, the stitcher 50 press-bonds the overlapping portion 56. The stitcher 50 is crimped from one side to the other side in the axial direction. Thus, in the stitcher 50 that crimps in one direction in the axial direction, the band base body 42 is likely to be displaced. This manufacturing method is particularly suitable for suppressing positional deviation when the overlapping portion 56 is pressure-bonded in one direction.

  The band base 42 is formed from a single carcass ply 28. In this band base 42, the band base 42 is likely to be displaced due to the pressure bonding of the overlapping portion 56, as compared with a band base having a plurality of carcass plies. This positional deviation mainly occurs between the outer peripheral surface 36a of the drum 36 and the rubber member (inner liner member 18a) in contact with the outer peripheral surface 36a. This positional deviation is more likely to occur as the radial thickness of the band base 42 is smaller. This manufacturing method is particularly suitable for the manufacturing method of the tire 2 in which the carcass 12 is composed of one carcass ply 28.

  In the tire 2, the sidewall 6 is located between the tread 4 and the carcass 12 near the end of the tread 4. This structure is called the TOS structure. On the other hand, in a tire having an SOT structure (not shown), the tread is located between the sidewall and the carcass near the end of the tread. In the method for manufacturing the tire 2 having the TOS structure, the thickness of the band base 42 in the radial direction when the carcass ply member 28a is pressure-bonded is smaller than that of the tire having the SOT structure. Therefore, in the method for manufacturing the tire 2 having the TOS structure, the band base 42 is likely to be displaced due to the pressure bonding. The manufacturing method according to the present invention is suitable for suppressing the positional deviation in the tire 2 having the TOS structure.

  Hereinafter, the effects of the present invention will be clarified by examples, but the present invention should not be limitedly interpreted based on the description of the examples.

[Example 1]
The tire of FIG. 1 was obtained by the manufacturing method according to the present invention using the molding apparatus of FIG. The pressure bonding pressure Pt and the pitch Dp were as shown in Table 1.

[Comparative Example 1-3]
When the polymerized part of the carcass ply member was pressure-bonded, it was not adsorbed by the adsorption holes. Moreover, the pressure bonding Pt was set as shown in Table 1. A tire was obtained in the same manner as in Example 1 except for the above.

[Example 2-5]
A tire was obtained in the same manner as in Example 1 except that the pressure bonding pressure Pt and the pitch Dp were set as shown in Table 2.

[Evaluation of misalignment]
A method for evaluating the displacement of the band base will be described with reference to FIG. In FIG. 5, the carcass ply member M is wound around the outer peripheral surface of the drum D. The overlapping portion of the carcass ply member M is pressure bonded by a stitcher. The dashed-dotted line L in FIG. 5 represents the center line of the carcass ply member M before being crimped. The center line is a line passing through the center of the carcass ply member M in the axial direction. The alternate long and short dash line L ′ represents the center line of the carcass ply member M (band base) after being crimped. A double-headed arrow G represents the magnitude of positional deviation between the center line L and the center line L '. The presence or absence of occurrence of this positional deviation G was evaluated. The results are shown in the columns of "misalignment" in Tables 1 and 2.

[Uniformity Evaluation]
The LRO (Lateral Runout) was measured for each tire. The results are shown in Tables 1 and 2 as an index with Comparative Example 1 being 100. The smaller this index, the better the LRO. The smaller this index, the better the uniformity.

[Evaluation of joint open]
The incidence of joint open was determined in the production of each tire. The results are shown in Tables 1 and 2. The smaller this value is, the lower the occurrence rate is, which is preferable.

  As shown in Tables 1 and 2, the manufacturing method of the example has a higher evaluation than the manufacturing method of the comparative example. From this evaluation result, the superiority of the present invention is clear.

  The method described above can be widely applied to the manufacture of tires.

2 ... Tire 18 ... Inner liner 18a ... Inner liner member 28 ... Carcass ply 28a ... Carcass ply member 34 ... Molding device 36 ... Drum 38 ... Band transfer 40. ..Shaping former 42 ... Band base 44 ... Band holder 46 ... Bead setter 48 ... Conveying device 50 ... Stitcher 52 ... Segment 54 ... Suction hole 56 ... Polymerization section

Claims (4)

(A) A step of winding the inner liner member around the drum,
(B) A step of winding a carcass ply member around the wound inner liner member to form a superposed portion of a front end portion and a rear end portion in the circumferential direction of the carcass ply member, and (C) an outer peripheral surface of the drum. A method for manufacturing a tire, comprising a step of pressure-bonding the polymerized portion with a stitcher in a state where the inner liner member is adsorbed by the formed adsorption holes to obtain a band substrate including the inner liner member and the carcass ply member.   The tire manufacturing method according to claim 1, wherein the pitch of the suction holes of the drum is 200 mm or more and 250 mm or less in the axial direction of the drum.   The method for manufacturing a tire according to claim 1 or 2, wherein in the step (C), the pressure for pressing the stitcher is 0.25 MPa or more and 0.40 MPa or less. (D) further comprising a step of holding the wound band base with a band holder and transporting the band base,
2. In the step (C), the overlapping portion is pressure-bonded by the stitcher supported by the band holder while the band holder moves relative to the drum toward a position holding the band base. 5. The method for manufacturing the tire according to any one of 3 to 3.

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